/*========================== begin_copyright_notice ============================

Copyright (C) 2017-2021 Intel Corporation

SPDX-License-Identifier: MIT

============================= end_copyright_notice ===========================*/

#include "Compiler/CISACodeGen/PositionDepAnalysis.hpp"
#include "GenISAIntrinsics/GenIntrinsicInst.h"
#include "Compiler/CodeGenPublic.h"
#include "Compiler/IGCPassSupport.h"
using namespace IGC;
using namespace llvm;

char PositionDepAnalysis::ID = 0;
#define PASS_FLAG "PositionDepAnalysis"
#define PASS_DESCRIPTION "Pos"
#define PASS_CFG_ONLY true
#define PASS_ANALYSIS true
IGC_INITIALIZE_PASS_BEGIN(PositionDepAnalysis, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)
IGC_INITIALIZE_PASS_DEPENDENCY(WIAnalysis)
IGC_INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
IGC_INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
IGC_INITIALIZE_PASS_DEPENDENCY(MetaDataUtilsWrapper)
IGC_INITIALIZE_PASS_END(PositionDepAnalysis, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)

namespace IGC {

PositionDepAnalysis::PositionDepAnalysis() : FunctionPass(ID) {
  initializePositionDepAnalysisPass(*PassRegistry::getPassRegistry());
}

bool PositionDepAnalysis::runOnFunction(llvm::Function &F) {
  CodeGenContext *ctx = getAnalysis<CodeGenContextWrapper>().getCodeGenContext();
  m_newURBEncoding = ctx->platform.hasLSCUrbMessage();
  if (ctx->type == ShaderType::VERTEX_SHADER && ctx->m_DriverInfo.PreventZFighting()) {
    visit(F);
  }
  return false;
}

void PositionDepAnalysis::visitCallInst(CallInst &I) {
  if (GenIntrinsicInst *intr = dyn_cast<GenIntrinsicInst>(&I)) {
    if (intr->getIntrinsicID() == GenISAIntrinsic::GenISA_URBWrite) {
      if (ConstantInt *index = dyn_cast<ConstantInt>(intr->getOperand(0))) {
        // position is written at offset 0 or 1
        if (index->isZero() || (m_newURBEncoding && index->getZExtValue() == 16) ||
            (!m_newURBEncoding && index->isOne())) {
          unsigned int baseSourceIndex = index->isZero() ? 6 : 2;
          for (unsigned int i = 0; i < 4; i++) {
            if (Instruction *instDep = dyn_cast<Instruction>(intr->getOperand(baseSourceIndex + i))) {
              UpdateDependency(instDep);
            }
          }
        }
      }
    }
  }
}

void PositionDepAnalysis::UpdateDependency(Instruction *inst) {
  auto it = m_PositionDep.insert(inst);
  if (it.second) {
    for (unsigned int i = 0; i < inst->getNumOperands(); ++i) {
      if (Instruction *srcInst = dyn_cast<Instruction>(inst->getOperand(i))) {
        UpdateDependency(srcInst);
      }
    }
  }
}
bool PositionDepAnalysis::PositionDependsOnInst(Instruction *inst) {
  return m_PositionDep.find(inst) != m_PositionDep.end();
}

} // namespace IGC
